Answer:
450 meters straight ahead
Step-by-step explanation:
As we know that displacement is the total vector displacement of the object from initial point to final point
As here the Alonzo moves in a straight line during the finish line which is at distance of 500 m
so initial displacement is given as

now for cool down he again moves back 50 meter along the same track in backward direction
so it is given as

so we can say that total displacement will be
straight ahead